The justices were unanimous in ruling that extending a buffer zone 35 feet from clinic entrances violates the First Amendment rights of protesters.

Chief Justice John Roberts said authorities have less intrusive ways to deal with problems outside the clinics.

While the court was unanimous in the outcome, Roberts joined with the four liberal justices to strike down the buffer zone on narrow grounds. In a separate opinion, Justice Antonin Scalia criticized Roberts’ opinion for carrying forward “this court’s practice of giving abortion-rights advocates a pass when it comes to suppressing the free-speech rights of their opponents.”

The case began when Boston-area grandmother Eleanor McCullen and other abortion opponents sued over the limits on their activities at Planned Parenthood health centers in Boston, Springfield and Worcester. At the latter two sites, the protesters say they have little chance of reaching patients arriving by car because they must stay 35 feet from the entrance to those buildings’ parking lots.

The organization said that the buffer zone has significantly reduced the harassment of patients and clinic employees. Before the 35-foot zone went into effect in 2007, protesters could stand next to the entrances and force patients to squeeze by, Planned Parenthood said.

There are no abortion clinics in the greater Fall River, Taunton or New Bedford areas.

Patients who visit Family Planning in Fall River and Taunton are referred to centers that perform abortion in Attleboro, Providence or Boston.

Most of the offices contacted did not want to comment on the ruling, whether or not they offered abortion services.

A representative of Family Planning in Fall River said she could not speak on the record. That office provides gynecological and reproductive health services but not abortions.

Four Women Health Services, an Attleboro clinic that offers gynecological services and abortion up to 20 weeks into pregnancy, said it had learned about the ruling and had “no comment.”

That was not the case at Health Imperatives, which runs Family Planning in New Bedford, Brockton, Attleboro and locations on the Cape. President and CEO Julia Kehoe expressed her disappointment in the ruling.

While Health Imperatives does not offer abortion, Kehoe said the ruling puts women’s health care in jeopardy.

She said that, while she doesn’t take free speech lightly, “safety trumps everything.”

“Not everyone going there is going for an abortion,” Kehoe said. “They offer other critical services. It could really prevent women’s health care.”

The ruling that will allow protesters to be close to entrances could also be intimidating to employees, Kehoe explained.

At Health Imperatives, patients are offered counseling services along with physical examinations.

“We want to make sure people have all the options,” Kehoe said. “There’s no pressure one way or another.”

Those who opt for abortion are referred to other clinics. Sometimes they are escorted by volunteers or counselors.

“No one makes that decision lightly,” Kehoe said. “After an agonizing decision, we want them to be safe.”

Martha “Marty” Walz, president and CEO of Planned Parenthood League of Massachusetts, said the league will need to find other ways to keep patients safe.

“Today’s ruling isn’t the end of the story — it can’t be,” Walz said. “Our top priority is to ensure the safety of our patients and staff, and we will work with local law enforcement and elected officials to protect public safety.”

Before 2007, a floating buffer zone kept protesters from approaching unwilling listeners any closer than 6 feet if they were within 18 feet of the clinic. The floating zone was modeled after a Colorado law that the Supreme Court upheld. That decision was not called into question in Thursday’s ruling.

Clinic officials said they are most concerned about safety because of past incidents of violence. In 1994, a gunman killed two receptionists and wounded five employees and volunteers at a Planned Parenthood facility and another abortion clinic in nearby Brookline. The most recent killing was in 2009, when Dr. George Tiller, who performed abortions, was shot in a church in Wichita, Kansas.

Abortion protesters said that other state and federal laws already protect health center workers and patients, as well as access to clinics.